On 12/10/2010 10:40 AM, Tom H wrote: > On Fri, Dec 10, 2010 at 8:43 AM, Steve Clark<sclark at netwolves.com> wrote: > >> I have a confusing problem. I have two centos 5,5 boxes. Both have >> sudo.i386 1.7.2p1-9.el5_5 >> installed >> >> I am using the same sudoers file, but the one on box A keeps trying to do >> DNS lookups while the one on box B does not. How do I disable this DNS >> lookup? >> > > Do both hosts have their hostnames in "/etc/hosts"? > > Do both hosts have "hosts: files dns" in "/etc/nsswitch.conf"? > _______________________________________________ > CentOS mailing list > CentOS at centos.org > http://lists.centos.org/mailman/listinfo/centos > > strace shows the DNS lookup. I have resolved the problem as far why they behaved differently. Someone had put an entry in /etc/resolv.conf when normally we run our own nameserver at 127.0.0.1. Putting a hostname and address in the /etc/hosts also fixed the problem. But I still don't understand why it wants to do a DNS lookup when I don't have Defaults fqdn in the sudoers file. Again here is part of an strace of sudo cat /etc/rc.local; ... socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4 connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.1")}, 28) = 0 fcntl64(4, F_GETFL) = 0x2 (flags O_RDWR) fcntl64(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 gettimeofday({1292009049, 862615}, NULL) = 0 poll([{fd=4, events=POLLOUT}], 1, 0) = 1 ([{fd=4, revents=POLLOUT}]) send(4, "\206r\1\0\0\1\0\0\0\0\0\0\5Z7070\tnetwolves\3com"..., 37, MSG_NOSIGNAL) = 37 poll([{fd=4, events=POLLIN}], 1, 5000) = 1 ([{fd=4, revents=POLLIN}]) ioctl(4, FIONREAD, [86]) = 0 recvfrom(4, "\206r\205\203\0\1\0\0\0\1\0\0\5Z7070\tnetwolves\3com"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.1")}, [16]) = 86 close(4) = 0 socket(PF_INET, SOCK_DGRAM, IPPROTO_IP) = 4 connect(4, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.1")}, 28) = 0 fcntl64(4, F_GETFL) = 0x2 (flags O_RDWR) fcntl64(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 gettimeofday({1292009049, 864056}, NULL) = 0 poll([{fd=4, events=POLLOUT}], 1, 0) = 1 ([{fd=4, revents=POLLOUT}]) send(4, "\324\305\1\0\0\1\0\0\0\0\0\0\5Z7070\tnetwolves\3com"..., 51, MSG_NOSIGNAL) = 51 poll([{fd=4, events=POLLIN}], 1, 5000) = 1 ([{fd=4, revents=POLLIN}]) ioctl(4, FIONREAD, [100]) = 0 recvfrom(4, "\324\305\205\203\0\1\0\0\0\1\0\0\5Z7070\tnetwolves\3com"..., 1024, 0, {sa_family=AF_INET, sin_port=htons(53), sin_addr=inet_addr("127.0.0.1")}, [16]) = 100 close(4) = 0 readlink("/proc/self/exe", "/usr/bin/sudo"..., 4095) = 13 -- Stephen Clark *NetWolves* Sr. Software Engineer III Phone: 813-579-3200 Fax: 813-882-0209 Email: steve.clark at netwolves.com http://www.netwolves.com -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos/attachments/20101210/6c685386/attachment-0005.html>